Karl mischke



(No Model.)

K. MISOHKE. SCREW GUTTING'TOOL.

No. 417,574. Patented Dec. 17, 1889:

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WITNESSES: l/VVE/VTOR Enron.

ATENT KARL MISOHKE, OF NEW YORK, N. Y.

SCREW-CUTTING TO'OL.

SPECIFICATION forming part of Letters Patent No. 417,574, dated December17, 1889.

Application filed February 28, 1889. Serial No. 301,553- (No model.)

To all whom it may concern:

Be it known that I, KARL MISOHKE, of the city, county, and State of NewYork, a citizen of the German Empire, have invented certain new anduseful Improvements in Screw-Outting Tools, of which the following is aspecification.

This invention relates to an improved screwcuttiug tool which isautomatically stopped whenever the required length of thread is cut andreleased from the threaded article, so as to permit the removal of thesame without necessitatin g the return of the threading device; and theinvention consists of a tool for cutting screw-threads which comprises atubular main piece or stock, fulcrumed and springactuated levers whichcarry the screw-cutting dies, and an interior screw-bolt that isconnected by a cross-head to a shiftable sleeve on the exterior of thetubular stock, said sleeve being provided with a beveled front part thatengages therear ends of the die-levers, so as to release the samewhenever the sleeve is shifted by the contact of the article tubularmain part or stock of my improved screw-cutting tool, which stock isprovided at the rear end with a slightly-tapering extension A, ofsmallerdiameter, by which latter it is inserted into one of the centersof a lathe. To lugs at the front part of the stock A are fulcrumedspring-actuated levers B B, which carry at their front en ds in suitabletransverse openings the screw-cuttin g dies 19 b, which are adjusted tothe proper size of shank to be threaded and fed forward when worn byadjusting-screws b and screwed firmly in position by clamp-screws 12 Atthe interior of the tubular stock A is arranged a shifting screw 0,which passes through athreaded hole-of a transverse crosspiece D, thatis guided in a slot 01 of the stock A, and secured at the outer ends toa circumferentially-grooved sleeve E, that is shifted forward orbackward on the stock A either by hand or by means of a forked leverapplied to the grooved part of the sleeve E, as desired. The front endof the shifting screw 0 is provided with a nicked head a, that isengaged by a suitable screwdriver inserted into the tubular stock A, soas to adjust thereby the shifting screw for the required length ofscrew-thread in the cross-piece -D. The front'part of the sleeve E isconicallybeveled and forms contact with the rear ends of the die-leversB when the sleeve E is moved forward on the stock, as shown in Fig. 1.In this position the dies Z) Z) are in a position to cut into the shankfed to the same, soasto produce a screw-thread thereon. As the shank isfed forward into the tubular stock A by the action of the cutting-diesthe end of the shank finally abuts against the head of the shiftingscrew 0 and produces the backwardly-shifting motion of the sleeve E, sothat the beveled front end of the same releases the rear ends of thedie-levers and permits the front ends of the same to be moved in anoutward direction by the action of springs B, which are interposedbetween the tubular stock A and the levers B. The dies clear thereby thethreaded shank and permit the removal of the same without turning thescrew-cutting tool in an opposite direction for removing it from saidshank.

By adjusting the shifting screw 0 in the stock any length of thread maybe cut on the shanks of rods, hooks, or other articles, the cuttingaction of the dies being automatically interrupted when ever the properlength of thread is out, as at that moment the shifting screw is pushedbackward and the sleeve shifted, the die-levers released, and the diesmoved away from the shank.

For adjusting the cutting-dies for threading different sizes of shankswithoutrequiring the resetting of the cutting-dies in the front ends ofthe die-levers a longitudinal rod F is secured by a clamp-screw f, orotherwise, in the front part of the stock at a point immediately betweentwo of the die-levers B, said rod being capable of longitudinal adjustment in said stock, so that its rear end may be set closer to orfarther away from the circumferential flange of the sliding sleeve E.The sliding sleeve E abuts by its circumferential flange f against therod l, which controls the forward shifting motion of the sliding sleeveE, and permits the setting of the cutting-dies to different sizes ofshanks to be threaded. The rear ends of the die-levers pass to a smalleror larger distance over the conical front end of the sleeve E, and setthereby the cutting-dies more or less close together, as required.

The automatical stop action is accomplished by the interior shiftingscrew 0 in the same manner as before described, whatever he the positionof the stop-rod F in the stock.

Having thus described my invention, I claim as new and desire to secureby Letters laten t 1. The combination of a tubular stock, springactuateddie-levers fnlcrumcd to said stock and provided with adjustablecuttingdies at their front ends, asliding sleeve placed on said stockand provided with a tapering front end, an adjustable shifting, screw10- cated at the interior of the stock, and acrosspiece connecting theshifting screw with said sleeve, said cross-piece being guided in atransverse slot of the stock, substantially as Set forth.

2. The combination, with a tubular stock, fulcru med and spring-actuateddie-levers having dies at their front ends, a sliding sleeve located onthe rear part of the stock and provided with a conically-tapering frontend, a shifting screw in said stock connected to said sliding sleeve,and an adjustable stop-rod passing longitudinally throughthe stock, soas to control the length of shifting motion of the sleeve, substantiallyas set forth.

In testimony that I claim the foregoing as my invention I have signed myname in presence of two subscribing witnesses.

KARL MISCIIKE.

